Low residue antiperspirant gel-solid stick compositions containing select gellants

ABSTRACT

Disclosed are anhydrous antiperspirant gel-solid stick compositions which comprise a particulate antiperspirant active; a solid non-polymeric gellant selected from the group consisting of 12-hydroxystearic acid, esters of 12-hydroxystearic acid, amides of 12-hydroxystearic acid, and combinations thereof, and an anhydrous liquid carrier having an average solubility parameter of from about 3 to about 13 (cal/cm 3 ) 0 .5, wherein the composition has a visible residue index of from about 11 to about 30 L-value, a product hardness of from about 500 gram.force to about 5,000 gram.force, a ratio of an elastic to viscous moduli of from about 0.1 to about 100. The refractive indices of the particulate antiperspirant active, solid non-polymeric gellant, and anhydrous liquid carrier are not matched. The solid non-polymeric gellant is preferably a crystalline material having an average particle size of less than about 1 μm, and/or having an elongated particle morphology having an aspect ratio of greater than about 2. These antiperspirant gel-solid stick compositions provide improved low residue performance, efficacy and aesthetics.

TECHNICAL FIELD

The present invention relates to antiperspirant compositions in the formof gel-solid sticks. In particular, the present invention relates toantiperspirant compositions in the form of gel-solid sticks that provideimproved low residue performance, efficacy and aesthetics, and whichcontain select gellants.

BACKGROUND OF THE INVENTION

There are many types of topical antiperspirant products that arecommercially available or otherwise known in the antiperspirant art.Most of these products are formulated as aerosol or pump sprays, roll-onliquids, creams, emulsions, gels, gel-solids, or other solid stickformulations, and comprise an astringent material, e.g. zirconium oraluminum salts or combinations thereof, incorporated into a suitablecarrier. These products are designed to provide effective perspirationand odor control while also being cosmetically acceptable during andafter application onto the axillary area or other areas of the skin.

Within this product group, solid antiperspirant sticks have becomeespecially popular among consumers. These antiperspirant sticks comprisea solid matrix within which the antiperspirant active material iscontained. The active can be solubilized in a liquid carrier comprisingwater, glycols and/or other alcohols, or maintained within a solidmatrix as dispersed solids in an anhydrous system. The solid stickswhich contain dissolved active often provide some low residueperformance, but tend to be wet or sticky during and immediately afterapplication to the skin, and more importantly, are often not aseffective in providing antiperspirant and deodorant performance as solidsticks containing dispersed particulate active. Although theantiperspirant sticks which contain particulate actives are moreeffective, they also tend to leave a higher visible residue on the skin.

There have been many attempts at producing anhydrous antiperspirantsticks which contain dispersed particulate antiperspirant active, andwhich also provide improved efficacy and low residue performance duringand after application to the skin, or which otherwise provide productclarity prior to (as a packaged product) or after such application (as aclear or low-residue film on the skin).

One such attempt involves the combination of particulate antiperspirantactive, gellants and liquid carrier in a gel stick, wherein all suchcomponents in the combination have matching refractive indices.Refractive index matching allows for more passage of light through thegel stick with less scattering of the light, thus resulting in productswhich appear more clear or translucent as a packaged composition or wheninitially applied topically to the skin. These gel sticks, however, areexpensive to make due to the cost of using raw materials having onlyselect matching refractive indices. These compositions are also verydifficult to formulate given that refractive index matching for a threecomponent system (particulate active, solvent and gellant) is extremelydifficult, and greatly limits the materials that can be used to preparesuch a formulation.

Another attempt at making low residue antiperspirant sticks involves theuse of gellants such as dibenzylidene alditols. These gellants, however,like many other gellants known in the art, are not acid stable andtherefore tend to interact with the antiperspirant active due to theacidic nature of the active. This interaction can result in reducedefficacy of the active, poor gel formation, and lower gel stability overextended periods during shipping or storage. This interaction may alsocause processing difficulties at the temperatures and holding timesoften used during the formulation and manufacturing process. Thesegellants are also commonly used in combination with glycol carriers orother solvents which tend to be wet and sticky and irritating to theskin.

Yet another attempt at making low residue antiperspirant sticks involvesthe use of residue masking agents such as non-volatile paraffinichydrocarbon fluids, phenyl trimethicone, low melting point waxes andcombinations thereof. These agents are used in combination with stearylalcohol or other high residue waxes commonly used in solidantiperspirant sticks. These agents help reduce visible residue duringand immediately after application of the solid stick to the skin, butalso tend to be associated with an oily or sticky skin feeling duringapplication. Moreover, although the visible residue is reduced in suchcompositions, there remains a visible residue on the skin when used incombination with high residue waxes such as stearyl alcohol, and thisreduced residue is still more visible or apparent than the topicalresidue left by antiperspirant sticks which contain solubilizedantiperspirant active.

Other attempts at improving low residue performance from anantiperspirant composition has focused on the use of anhydrousantiperspirant creams. These creams can be applied to the skin byconventional means, or by a cream applicator device, and results in verylow residue during and immediately after application to the skin. Thesecompositions comprise particulate active dispersed throughout ananhydrous carrier, and either contained within a solid-like matrix orthickened with an inorganic or polymeric gellant or thickening agent.Many consumers, however, still prefer the convenience of using a solidantiperspirant stick, even if the solid stick tends to leave a highervisible residue on the skin.

A recent method of making low residue antiperspirant sticks is describedin U.S. Pat. No. 5,429,816, issued to Hofrichter et al. on Jul. 4, 1995,which description is hereby incorporated by reference herein. Theantiperspirant sticks provide low visible residue during and immediatelyafter application to the skin, and are physically and chemically stableover extended periods of time. The improved antiperspirant stickscomprise a dual gellant system having a primary gellant such as12-hydroxystearic acid or esters or amides thereof and a secondarygellant such as n-acyl amino acid derivatives. Formation of such anantiperspirant stick with such a dual gellant system has beencharacterized as a "gel-solid" antiperspirant stick.

An antiperspirant gel-solid, such as that described by Hofrichter et.al., is an antiperspirant stick having a three-dimensional,non-polymeric, gel network in which solvent is contained or trapped.These gel-solids are typically formed by solubilizing the gellant in thesolvent at temperatures above the melt point of the gellant and attemperatures at which the melted gellant is soluble in the solvent, andthen cooling the composition to form the desired gel-solid composition.The low residue gel-solids described by Hofrichter et al. are remarkablystable, both physically and chemically, and will maintain the desiredproduct hardness over an extended period of time. The gel-solidsdescribed by Hofrichter et al., however, are limited to select dualgellant systems and do not include or otherwise describe any method ofmaking a low-residue antiperspirant gel-solid stick containing any othergellant or gellant system.

It has now been found that other low-residue gel-solids can beformulated without reliance upon the select combination of gellantsdescribed by Hofrichter et al. The new low-residue gel-solids areanhydrous systems which comprise from about 0.5% to about 60% by weightof particulate antiperspirant active; from about 1% to about 15% byweight of a solid non-polymeric gellant selected from the groupconsisting of 12-hydroxystearic acid, esters of 12-hydroxystearic acid,amides of 12-hydroxystearic acid, and combinations thereof; from about10% to about 80% by weight of an anhydrous liquid carrier for the solidnon-polymeric gellant having an average solubility parameter((cal/cm³)⁰.5) of from about 3 about 13; wherein the composition has avisible residue index of from about 11 to about 30 L-value, a producthardness of from about 500 gram.force to about 5,000 gram.force, a ratioof an elastic modulus (G') to a viscous modulus (G") of from about 0.1to about 100. The composition does not require refractive index matchingof the particulate antiperspirant active, solid non-polymeric gellant,and anhydrous liquid carrier to obtain low residue performance. Thecompositions preferably comprise gellant crystalline particles having anaverage particle size of less than about 1 μm, and/or an elongatedparticle morphology defined by an aspect ratio of greater than about 2.

It is therefore an object of the present invention to provide ananhydrous antiperspirant gel-solid stick containing particulateantiperspirant active which provides improved low residue performanceand improved antiperspirant efficacy, and further to provide such acomposition without reliance upon specific gellants such asdibenzylidene alditols or dual gellant systems containing n-acyl aminoacid derivatives. It is a further object of the present invention toprovide such a composition without reliance upon refractive indexmatching of component materials, or the use of solubilizedantiperspirant active, to obtain product clarity or low residueperformance. It is yet another object of the present invention toprovide such a composition using only gellants selected from the groupconsisting of 12-hydroxystearic acid, esters of 12-hydroxystearic acid,amides of 12-hydroxystearic acid, and combinations thereof.

SUMMARY OF THE INVENTION

The present invention is directed to anhydrous antiperspirant gel-solidstick compositions which comprise from about 0.5% to about 60% by weightof particulate antiperspirant active; from about 1% to about 15% byweight of a solid non-polymeric gellant selected from the groupconsisting of 12-hydroxystearic acid, esters of 12-hydroxystearic acid,amides of 12-hydroxystearic acid, and combinations thereof; from about10% to about 80% by weight of an anhydrous liquid carrier for the solidnon-polymeric gellant having an average solubility parameter of fromabout 3 to about 13 (cal/cm³)⁰.5 ; wherein the composition has a visibleresidue index of from about 11 to about 30 L-value, a product hardnessof from about 500 gram.force to about 5,000 gram.force, a rheologyprofile defined by a ratio of an elastic modulus (G') to a viscousmodulus (G") of from about 0.1 to about 100. The refractive indices ofthe particulate antiperspirant active, the solid non-polymeric gellant,and the anhydrous liquid carrier are not matched. The compositionspreferably comprise crystalline gellant particles having an averageparticle size of less than about 1 μm and/or a particle morphologyhaving an aspect ratio of greater than about 2.

It has been found that the antiperspirant gel-solid stick compositionsof the present invention can provide low residue performance without theneed to use solubilized antiperspirant active, and without reliance uponselect low residue gellants such as dibenzylidene alditols, gellantcombinations containing n-acyl amino acid derivatives, or other gellantsother than those select gellants described herein. This is accomplishedby formulating an anhydrous gel-solid stick composition having theselect hardness and rheology profile preferably provided by anon-polymeric, three-dimensional crystalline gel network made up ofsmall, elongated crystalline particles having an average particle sizeof less than about 1 μm and/or a particle morphology defined by anaspect ratio of at least about 2, wherein the solid non-polymericgellant used to provide these gellant or composition characteristics isselected from the group consisting of 12-hydroxystearic acid, esters of12-hydroxystearic acid, amides of 12-hydroxystearic acid, andcombinations thereof.

DETAILED DESCRIPTION OF THE INVENTION

The antiperspirant gel-solid stick compositions of the present inventionare anhydrous systems which are dispersions of particulateantiperspirant active held or contained within a non-polymericcrystalline gel-solid matrix.

The term "anhydrous" as used herein means that the antiperspirantgel-solid stick composition of the present invention, and the essentialor optional components thereof other than the particulate antiperspirantactive, are substantially free of added or free water. From aformulation standpoint, this means that the antiperspirant gel-solidstick compositions of the present invention preferably contain less thanabout 5%, preferably less than about 3%, more preferably less than about1%, most preferably zero percent, by weight of free or added water,other than the water of hydration typically associated with theparticulate antiperspirant active prior to formulation.

The term "low residue" as used herein refers generally to the visibleresidue left on the applied areas of the skin during or immediatelyafter application, and more specifically refers to the visible residueindex of the composition as defined by the methodology describedhereinafter.

The term "ambient conditions" as used herein refers to surroundingconditions under about one atmosphere of pressure, at about 50% relativehumidity, and at about 25° C., unless otherwise specified.

The term "substantially free" as used herein, unless otherwisespecified, refers to preferred negative limitations of the compositionsof the present invention, and are directed to the preferred amount orconcentration of inorganic thickening agents, organic polymericthickening agents, dibenzylidene alditol gellants, n-acyl amino acidderivatives, or combinations thereof, in the composition. The term"substantially free" means that the compositions preferably contain lessthan an effective amount of such agents when used alone to provide anythickening or measurable viscosity increase to the composition. In thiscontext, the negative limitations pertain only to those thickening orgelling agents which are also solid under ambient conditions, and whichare not silicone containing materials or polymeric derivatives of12-hydroxystearic acid. Generally, the compositions preferably containless than 5%, preferably less than 2%, more preferably less than 1%,even more preferably less than 0.5%, most preferably zero percent, ofsuch agents by weight of the composition. Examples of inorganicthickening agents to which the above-described negative limitationspertain include finely divided or colloidal silicas, fumed silicas, andsilicates, which includes montmorillonite clays and hydrophobicallytreated montmorillonites, e.g., bentonites, hectorites and colloidalmagnesium silicates. Examples of organic polymeric gelling agents towhich the above-described negative limitations pertain include organicpolymers well known in the antiperspirant or personal care art for usein providing gelling or thickening or other physical or aestheticbenefits to a composition, specific examples of which includehydrogenated butylene/ethylene/styrene copolymer, polyethylene, oxidizedpolyethylene, polyamides, acrylic acid polymers, ethylene acrylatecopolymers, and other organic polymeric gelling agents described inRheological Properties of Cosmetics and Toiletries, Edited by DennisLaba, published by Marcel Dekker, In., New York (1993), whichdescription is incorporated herein by reference.

The term "substituted" as used herein, unless otherwise specified,refers to chemical moieties or substituents known or otherwise suitablefor attachment to the compounds or other chemical materials described orreferred to herein. These substituents include, but are not limited to,those listed and described in C. Hansch and A. Leo, SubstituentConstants for Correlation Analysis in Chemistry and Biology (1979),which listing and description are incorporated herein by reference.Examples of such substituents include, but are not limited to, alkyl,alkenyl, alkoxy, hydroxy, oxo, nitro, amino, aminoalkyl (e.g.,aminomethyl, etc.), cyano, halo (e.g., chlorine, fluorine, bromine,iodine), carboxy, alkoxyaceyl (e.g., carboethoxy, etc.), thiol, aryl,cycloalkyl, heteroaryl, heterocycloalkyl (e.g., piperidinyl,morpholinyl, pyrrolidinyl, etc.), imino, thioxo, hydroxyalkyl, aryloxy,arylalkyl, amides, esters, ethers, combinations thereof, and the like.

The term "n-acyl amino acid derivatives" refers to gellants selectedfrom the group consisting of n-acyl amino acid amides, n-acyl amino acidesters prepared from glutamic acid, lysine, glutamine, apartic acid, andcombinations thereof, and which are specifically disclosed in U.S. Pat.No. 5,429,816.

The terms "alkyl" and "alkenyl" as used herein, unless otherwisespecified, refer to substituted or unsubstituted, branched, cyclic orlinear, hydrocarbons having from 1 to about 22 carbon atoms.

The term "volatile" as used herein refers to materials which have avapor pressure under ambient conditions of at least about 0.2 mm of Hg.Conversely, the term "non-volatile" as used herein refers to materialswhich have no measurable vapor pressure or which have a vapor of lessthan about 0.2 mm of Hg under ambient conditions.

The solid non-polymeric gellant, antiperspirant active and anhydrousliquid carrier components of the gel-solid stick compositions herein arepreferably not refractive index matched, and more preferably have atleast two of such components with refractive indices (η_(D)) that differby at least about 0.02, more preferably by at least about 0.04.

The antiperspirant gel-solid stick compositions of the present inventioncan comprise, consist of, or consist essentially of the essentialelements and limitations of the invention described herein, as well asany of the additional or optional ingredients, components, orlimitations described herein.

As percentages, parts and ratios are by weight of the total composition,unless otherwise specified. All such weights as they pertain to listedingredients are based on the specific ingredient level and, therefore,do not include solvents, carriers, by-products, filler or other minoringredients that may be included in commercially available materials,unless otherwise specified.

Product Characteristics

The antiperspirant gel-solid stick compositions of the present inventionare characterized in terms of product hardness, visible residue index,and a rheology profile defined by a ratio of an elastic to viscousmoduli. Each of these characteristics is defined in accordance with themethodologies and other limitations described hereinafter.

a) Hardness

The antiperspirant gel-solid stick compositions of the present inventionhave a product hardness of from about 500 gram.force to about 5,000gram.force, preferably from about 750 gram.force to about 2,000gram.force, more preferably from about 800 gram.force to about 1,400gram.force.

The term "product hardness" as used herein is a reflection of how muchforce is required to move a penetration cone a specified distance and ata controlled rate into an antiperspirant gel-solid stick compositionunder the following test conditions. Higher values represent harderproduct, and lower values represent softer product. These values aremeasured at 27° C., 15% relative humidity, using a TA-XT2 TextureAnalyzer, available from Texture Technology Corp., Scarsdale, N.Y.,U.S.A. The product hardness value as used herein represents the amountof force required to move a standard 45° angle penetration cone throughthe composition for a distance of 10 mm at a rate of 2 mm/second. Thestandard cone is available from Texture Technology Corp., as part numberTA-15, and has a total cone length of about 24.7 mm, angled cone lengthof about 18.3 mm, a maximum diameter of the angled surface of the coneof about 15.5 mm. The cone is a smooth, stainless steel construction andweighs about 17.8 grams.

b) Residue

The antiperspirant gel-solid stick compositions of the present inventionhave a visible residue index of from 11 to about 30 L-value, preferablyfrom about 11 to about 25 L-value, more preferably from 11 to about 20L-value. The term "visible residue index" as used herein refersgenerally to the extent to which the composition of the presentinvention is visibly apparent as a thin topical film after applicationto the skin, and more specifically refers to visible residue values(expressed as an L-value on the L, a, b color scale) as measured inaccordance with the following methodology, performed at 27° C., underatmospheric pressure, and at 15% relative humidity on antiperspirantstick compositions having a product hardness of from about 500gram.force to about 5,000 gram.force.

A piece of black felt, approximately 10 cm×30 cm, is attached to amovable horizontal slide which is movably attached or fixed to a largermechanical unit. An example of a suitable piece of black felt for useherein is Supreme Robe Velour, FN-6554, Color 404L, Style 31854,available from So-Fro Fabrics, Evendale, Ohio, U.S.A. An example of asuitable mechanical assembly for use herein is the Release and AdhesionTester, Serial No. A-14934, manufactured by Testing Machines, Inc.,Amityville, N.Y., U.S.A., or a Velmex Unislide Positioning System,Unislide assembly series (MB6000), available from Velmex, Inc.,Bloomfield, N.Y., U.S.A. An antiperspirant stick composition containedwithin and partially extending out about 0.5 cm from a conventionalpackage or container is positioned perpendicular to and above theattached piece of felt, such that the product extending out of thepackage or container is facing the piece of felt and the surroundingpackage is positioned away from the piece of felt. The surroundingpackage is positioned in place using a mechanical arm or other devicesuitable for applying the requisite movement to the product as describedherein.

The antiperspirant stick composition is then slowly moved toward andallowed to gently contact the attached piece of black felt. A 1,000 gramweight is placed on the product sample so that the product continuouslycontacts the piece of black felt during testing. The weighted sample isthen moved repeatedly back and forth across the piece of felt at a fixedspeed (about 3 cm/second), and with a fixed amount of applied pressureprovided by the weighted product, until the about 1.75 grams of theantiperspirant stick composition is evenly applied over a 5 cm×20 cmarea of the piece of black felt. The piece of felt is then carefullyremoved from the apparatus.

A calibrated Minolta CR-300 chromameter (available from Minolta Corp.,Ramsey, N.J., U.S.A.) is then used to measure the L-value (on the L,a,bcolor scale) of the applied surface area. First, a template is placed ontop of the piece of felt to facilitate the Minolta readings. Templatedimensions are 5 cm×20 cm. The template has twelve circular openings(2.2 cm diameter) positioned within the template, each openingpositioned centrally within adjacent 6.5 cm² areas of the templatesurface. The template is positioned over the applied surface area of thepiece of felt such that each of the twelve circular openings covers anon-overlapping area of the applied surface. The chromameter's view portis fitted into each of the circular openings and L-value measurementstaken. An average L-value is then determined for the twelve measurements(standard deviation of less than about 0.8) which then corresponds tothe visible residue index as described herein.

It has been found that there is a correlation between the visibleresidue index range defined herein and the average particle size of thecrystalline gellant particles in the antiperspirant gel-solid stickcomposition of the present invention. Generally, as the average particlesize of crystalline gellant particles in the composition decreases, lowresidue performance improves. In particular, it has been found that avisible residue index of from about 11 to about 30 L-value correlateswith an average crystalline gellant particle size of less than about 1μm, and/or a crystalline gellant particle morphology characterized byone dimensional crystalline growth such as that resulting in crystallinefilaments, fibers, strings or other elongated particles, wherein theaspect ratio as defined by the major and minor axis of the crystallineparticle is greater than about 2, preferably greater than about 6.Conversely, solid compositions containing crystalline gellant particlesgreater than 1 μm (average particle diameter) have a visible residueindex of greater than 30 L-value. In view of this correlation betweenvisible residue index values and average crystalline particle size orelongated particle morphology, the visible residue index measurement cannow be used as an alternative means for establishing average crystallinegellant particle size or crystalline gellant morphology, at least to theextent that such average particle size is less than about 1 μm.

c) Rheology

The antiperspirant stick compositions of the present invention aregel-solids having the select rheology profile defined herein. Thisrheology profile is defined herein in terms of the elastic (G') toviscous (G") moduli ratio (G'/G") of the gel-solid stick composition. Toprovide the requisite rheology, the gel-solid stick compositions musthave a G'/G" ratio of from about 0.1 to about 100, preferably from about0.1 to about 50, more preferably from about 1 to about 20, even morepreferably from about 5 to about 20. This ratio represents the extent towhich the gel-solid stick compositions herein exhibit solid characterand the extent to which the compositions exhibit liquid or fluidcharacter, and specifically refers to the numerical ratio G'/G" asdetermined by the following methodology.

The elastic modulus is a measurement which correlates with the solidcharacter of the gel-solid stick compositions herein, and the viscousmodulus is a measurement which correlates with the fluid or liquidcharacter of the gel-solid stick compositions herein. Measurements forG' and G" for purposes of defining the composition of the presentinvention are determined under ambient conditions using conventionaltechniques well known in the formulation arts. For example, a BohlinStress-Strain Rheometer, available from Bohlin Reologi, Cranberry, N.J.,can be used using a cone (about 1°) and plate configuration. About 1.0mg of the product is carefully removed for the composition with minimalapplication of shear force and is then placed between the cone and platefixtures for measurement of G' and G".

It has been found that the gel-solid stick compositions of the presentinvention exhibit improved low residue performance when formulated asdescribed herein, wherein the composition has the select G'/G" ratiodescribed hereinabove, especially when the defined rheology isassociated with a crystalline gel matrix having a preferred smallparticle size and/or particle morphology as described herein. Thesegel-solid stick formulations spread smoothly over the skin, and shearquickly and melt during such spreading to form a thin, low residue filmover the applied surface.

In particular, it has been found that the gel-solid stick compositionsof the present invention have rheology characteristics that result inimproved performance, especially low residue performance. These selectgel-solid compositions as defined herein behave as solids prior toapplication while maintained within a canister or other package, butbehave more as liquids or fluids during or immediately after applicationto the skin. In other words, the solid compositions shear thin duringapplication to the skin, melt or almost melt (except for particulateactive which remains unmelted) during the shear thinning application,thus resulting in a thin, low residue, liquid or fluid film on the skinduring or immediately after topical application to the skin. The appliedfilm is clear or has very low visible residue, and remains substantiallyas such over extended periods of time after application.

Antiperspirant Active

The antiperspirant gel-solid stick compositions of the present inventioncomprise particulate antiperspirant active suitable for application tohuman skin. These particulate actives must remain substantiallyunsolubilized as dispersed or precipitated solids in the anhydrous orsubstantially anhydrous systems as described herein. The concentrationof particulate active in the composition should be sufficient to providethe desired perspiration wetness and odor control from theantiperspirant gel-solid stick formulation selected.

The antiperspirant gel-solid stick compositions of the present inventionpreferably comprise particulate antiperspirant active at concentrationsof from about 0.5% to about 60%, more preferably from about 5% to about35%, by weight of the composition. These weight percentages arecalculated on an anhydrous metal salt basis exclusive of water and anycomplexing agents such as glycine, glycine salts, or other complexingagents. The particulate antiperspirant active as formulated in thecomposition are in the form of dispersed solid particles having apreferred average particle size or diameter of less than about 100 μm,more preferably from about 15 μm to about 100 μm, even more preferablyfrom about 20 μm to about 100 μm. Also preferred are dispersed solidparticulates having an average particle size or diameter of less thanabout 2 μm, even more preferably from less than about 0.4 μm. It hasbeen found that antiperspirant active particles within the preferredparticle size ranges provide lower visible residue performance from thegel-solid compositions herein than other less preferred particle sizeranges.

The antiperspirant active for use in the antiperspirant gel-solid stickcompositions of the present invention include any compound, compositionor other material having antiperspirant activity. Preferredantiperspirant actives include the astringent metallic salts, especiallythe inorganic and organic salts of aluminum, zirconium and zinc, as wellas mixtures thereof. Particularly preferred are the aluminum andzirconium salts, such as aluminum halides, aluminum chlorohydrate,aluminum hydroxyhalides, zirconyl oxyhalides, zirconyl hydroxyhalides,and mixtures thereof.

Preferred aluminum salts for use in the antiperspirant gel-solid stickcompositions include those which conform to the formula:

    Al.sub.2 (OH).sub.a Cl.sub.b ·x H.sub.2 O

wherein a is from about 2 to about 5; the sum of a and b is about 6; xis from about 1 to about 6; and wherein a, b, and x may have non-integervalues. Particularly preferred are the aluminum chlorhydroxides referredto as "5/6 basic chlorhydroxide", wherein a=5, and "2/3 basicchlorhydroxide", wherein a=4. Processes for preparing aluminum salts aredisclosed in U.S. Pat. No. 3,887,692, Gilman, issued Jun. 3, 1975; U.S.Pat. No. 3,904,741, Jones et al., issued Sep. 9, 1975; U.S. Pat. No.4,359,456, Gosling et al., issued Nov. 16, 1982; and British PatentSpecification 2,048,229, Fitzgerald et al., published Dec. 10, 1980, allof which are incorporated herein by reference. Mixtures of aluminumsalts are described in British Patent Specification 1,347,950, Shin etal., published Feb. 27, 1974, which description is also incorporatedherein by reference.

Preferred zirconium salts for use in the antiperspirant gel-solid stickcompositions include those which conform to the formula:

    ZrO(OH).sub.2-a Cl.sub.a ·x H.sub.2 O

wherein a is from about 1.5 to about 1.87; x is from about 1 to about 7;and wherein a and x may both have non-integer values. These zirconiumsalts are described in Belgian Patent 825,146, Schmitz, issued Aug. 4,1975, which description is incorporated herein by reference.Particularly preferred zirconium salts are those complexes whichadditionally contain aluminum and glycine, commonly known as ZAGcomplexes. These ZAG complexes contain aluminum chlorhydroxide andzirconyl hydroxy chloride conforming to the above described formulas.Such ZAG complexes are described in U.S. Pat. No. 3,679,068, Luedders etal., issued Feb. 12, 1974; Great Britain Patent Application 2,144,992,Callaghan et al., published Mar. 20, 1985; and U.S. Pat. No. 4,120,948,Shelton, issued Oct. 17, 1978, all of which are incorporated herein byreference.

The antiperspirant gel-solid stick compositions of the present inventioncan also be formulated to comprise other dispersed solids or othermaterials in addition to or in place of the particulate antiperspirantactive. Such other dispersed solids or other materials include anymaterial known or otherwise suitable for topical application to humanskin. The antiperspirant gel-solid stick compositions can also beformulated as gel-solid stick compositions which contain noantiperspirant or other active material; particulate or otherwise.

Gellant

The antiperspirant gel-solid stick compositions of the present inventioncomprise select non-polymeric gellants. These select gellants formwithin the composition a crystalline matrix within which an anhydrousliquid carrier or other liquid component of the composition is trappedor contained. These select gellants are solids under ambient conditions,and preferably form crystalline particles having an average particlediameter and particle morphology as described hereinafter.

The select gellants for use in the antiperspirant gel-solid stickcompositions of the present invention are selected from the groupconsisting of 12-hydroxystearic acid, esters of 12-hydroxystearic acid,amides of 12-hydroxystearic acid and combinations thereof. The selectgellants include those solid gellants which correspond to the followingformula: ##STR1## wherein R₁ is OR₂ or NR₂ R₃ ; and R₂ and R₃ arehydrogen, or an alkyl, aryl, or arylalkyl radical which is branchedlinear or cyclic and has from about 1 to about 22 carbon atoms;preferably, from about 1 to about 18 carbon atoms. R₂ and R₃ may beeither the same or different; however, at least one is preferably ahydrogen atom.

The select gellant is preferably selected from the group consisting of12-hydroxystearic acid, 12-hydroxystearic acid methyl ester,12-hydroxystearic acid ethyl ester, 12-hydroxystearic acid stearylester, 12-hydroxystearic acid benzyl ester, 12-hydroxystearic acidamide, isopropyl amide of 12-hydroxystearic acid, butyl amide of12-hydroxystearic acid, benzyl amide of 12-hydroxystearic acid, phenylamide of 12-hydroxystearic acid, t-butyl amide of 12-hydroxystearicacid, cyclohexyl amide of 12-hydroxystearic acid, 1-adamantyl amide of12-hydroxystearic acid, 2-adamantyl amide of 12-hydroxystearic acid,diisopropyl amide of 12-hydroxystearic acid, and mixtures thereof; evenmore preferably, 12-hydroxystearic acid, isopropyl amide of12-hydroxystearic acid, and combinations thereof. Preferred is12-hydroxystearic acid.

The concentration of the select gellants in the compositions may varywith each antiperspirant gel-solid stick formulation, especially witheach selected anhydrous liquid carrier of the formulation, but suchconcentrations will generally range from about 0.1% to about 20%,preferably from about 1% to about 15%, more preferably from about 3% toabout 12%, by weight of the composition.

The antiperspirant gel-solid stick composition is substantially free ofinorganic (non-silicone containing) thickening agents, organic polymericthickening agents, and organic gellants other than the select gellantsdescribed hereinabove. In this context, "substantially free" means thatthe compositions contain less than an effective amount of such agents orother organic gellants that when used alone would provide any thickeningor measurable viscosity increase to the composition under ambientconditions. Generally, the compositions preferably contain less than 5%,more preferably less than 1%, even more preferably less than 0.5%, mostpreferably zero percent, of such agents by weight of the composition.The term "substantially free" does not, however, pertain to the use ofthe preferred nucleating agents (described hereinafter).

The select gellants for use in the antiperspirant gel-solid stickcompositions must melt and form a solution or other homogenous liquid orliquid dispersion with the selected anhydrous liquid carrier, and at theselected gellant and liquid carrier concentrations, at a processingtemperature of from about 28° C. to about 250° C., preferably from about28° C. to about 100° C., more preferably from about 28° C. to about 78°C. The melted gellant is typically dissolved by or dispersed throughoutthe selected liquid carrier to thus form a solution or other homogenousliquid. The solution or other homogenous liquid, and other essential andoptional ingredients, are preferably combined in accordance with themanufacturing method described herein or other conventional or otherwiseknown technique, and then placed in a suitable package as a flowablesolution or homogenous liquid, and then allowed to solidify and form thedesired solid gel matrix within the composition as the temperaturereturns to ambient temperature and drops to below the solidificationpoint of the composition.

In selecting a combination of solid non-polymeric gellant and liquidcarrier for use in the antiperspirant gel-solid stick compositions, thecombination should allow for the development of a crystalline gellantmatrix within the composition wherein the component crystallineparticles preferably have an average particle size of less than about 1μm, more preferably less than about 0.4 μm, even more preferably lessthan about 0.2 μm, most preferably from about 0.001 μm to about 0.2 μm,and/or wherein the crystalline particles have the requisite elongatedmorphology described herein, wherein particle size is measured ordetermined by the methods described herein or by methods well-known tothose skilled in the art such as light or electron microscopy. Thegel-solid stick compositions can be prepared by methods well known inthe formulation art for making gel-solids having minimal crystallineparticle size or the preferred elongated particle morphology. Thegel-solid stick compositions are preferably prepared by the selectmethods described hereinafter directed to minimizing crystallineparticle size and/or establishing the preferred crystalline particlemorphology.

These select gellants are especially effective when used in combinationwith anhydrous carrier liquids such as volatile silicones, especiallyvolatile cyclomethicone. These gellants are most preferably used incombination with a liquid carrier comprising a volatile silicone and/ora non-volatile silicone (e.g., non-volatile dimethicones or otherorganofunctional siloxanes) and/or a non-volatile organic carrier.

Preferred particle morphology

The select gellants for use herein preferably include those crystallinegellants that inherently form, or can be formulated or otherwise made toform, elongated crystalline particles having an aspect ratio greaterthan about 2, preferably greater than about 6. These elongated crystalspreferably have an average particle size as measured along a minor axisof the elongated crystal of less than 1 μm, more preferably less thanabout 0.4 μm, even more preferably less than about 0.2 μm, mostpreferably from about 0.2 μm to about 0.001 μm.

The gel-solid stick compositions containing these preferred elongatedcrystals can be prepared by methods described herein, or by methodsotherwise known in the formulation art for formulating gel matricescomprising these elongated crystalline particles.

The "aspect ratio" as used herein to define preferred embodiments of thegel-solid stick compositions herein can be determined by measuring orotherwise determining the ratio of the length of the major axis of thecrystalline particles to the length of the minor axis of the crystallineparticles. This length ratio of the major to minor axis is characterizedas the aspect ratio referred to herein. The aspect ratio can bedetermined by conventional or otherwise known light or electronmicroscopy methods, wherein the crystalline particles are measured formajor and minor axis dimensions, or are otherwise observed by suchmethods to clearly have an apparent elongated crystalline structure withan aspect ratio substantially greater than about 2, preferably greaterthan about 6.

It has been found that these crystalline gellants having the selectaspect ratios defined herein, provide the antiperspirant gel-solid stickcompositions a three-dimensional crystalline structure that can providethe composition with the requisite low residue performance, elastic toviscous moduli ratio, and product hardness as defined herein. It isbelieved that this crystalline morphology is especially effective inproviding a crystalline matrix within the composition that provides fora strong interlocking gel-solid matrix network, but which also comprisescrystalline particles that are sufficiently small in size so as tocontribute minimally to visible residue when applied topically to theskin.

It has also been found that the preferred crystalline matrix helpsprovide the gel-solid stick compositions with a melt profile thatcontributes to low residue performance. This preferred melt profilerefers to the temperature at which the antiperspirant gel-solid stickcomposition begins to melt, and the temperature range within which thecomposition is completely melted, except for any dispersedantiperspirant particulates or other high melting point components. Thetemperature at which the composition begins to melt is determined bymeasuring a Differential Scanning Calorimeter (DSC) onset temperature.The temperature range within which the composition is completely meltedis determined by no additional heat infusion. Preferred embodiments ofthe gel-solid stick compositions herein have a DSC onset temperature offrom about 25° C. to about 85° C., preferably from about 27° C. to about65° C., more preferably from about 30° C. to about 60° C., even morepreferably from about 35° C. to about 50° C. These preferredcompositions having the select melt profile provide improved cosmeticsor aesthetics when applied topically to the skin, and especially providereduced feeling of wetness, stickiness or product softness during andimmediately after application. The select melt profile also helps tofurther reduce the visible residue index of the composition, thusfurther improving lower residue performance.

Anhydrous Liquid carrier

The anhydrous antiperspirant gel-solid stick compositions of the presentinvention comprise an anhydrous liquid carrier for the crystallinegellant described hereinbefore. The anhydrous liquid carrier is liquidunder ambient conditions, and preferably has a low viscosity to providefor improved spreading on the skin.

Concentrations of the anhydrous liquid carrier in the gel-solid stickcomposition will vary primarily with the type and amount of theanhydrous liquid carrier, the solid non-polymeric gellant, and thesolubility of the solid non-polymeric gellant in the anhydrous liquidcarrier. Preferred concentrations of the anhydrous liquid carrier arefrom about 10% to about 80%, preferably from about 30% to about 70%,more preferably from about 45% to about 70%, by weight of thecomposition.

The anhydrous liquid carrier comprises one or more liquid carrierssuitable for topical application to human skin. These liquid carriersmay be organic, silicone-containing or fluorine-containing, volatile ornon-volatile, polar or non-polar, provided that the liquid carrier formsa solution or other homogenous liquid or liquid dispersion with theselected non-polymeric gellant at the selected gellant concentration ata temperature of from about 28° C. to about 250° C., preferably fromabout 28° C. to about 100° C., preferably from about 28° C. to about 78°C.

The anhydrous liquid carrier has a solubility parameter of from about 3to about 13 (cal/cm³)⁰.5, preferably from about 5 to about 11(cal/cm³)⁰.5, more preferably from about 5 to about 9 (cal/cm³)⁰.5.Solubility parameters for the liquid carriers or other materials, andmeans for determining such parameters, are well known in the chemicalarts. A description of solubility parameters and means for determiningthem are described by C. D. Vaughan, "Solubility Effects in Product,Package, Penetration and Preservation" 103 Cosmetics and Toiletries47-69, October 1988; and C. D. Vaughan, "Using Solubility Parameters inCosmetics Formulation", 36 J. Soc. Cosmetic Chemists 319-333,September/October, 1988, which descriptions are incorporated herein byreference.

The anhydrous liquid carrier preferably comprises a modified ororganofunctional silicone carrier selected from the group consisting ofpolyalkylsiloxanes, polyalkyarylsiloxanes, polyestersiloxanes,polyethersiloxane copolymers, polyfluorosiloxanes, polyaminosiloxanes,and combinations thereof. These modified silicone carriers must beliquid under ambient conditions, and have a viscosity of less than about100,000 centistokes, preferably less than about 500 centistokes, morepreferably from about 1 centistoke to about 50 centistokes; and evenmore preferably from about 1 centistoke to about 20 centistokes. Thesemodified silicone carriers are generally known in the chemical arts,some examples of which are described in 1 Cosmetics, Science andTechnology 27-104 (M. Balsam and E. Sagarin ed. 1972); U.S. Pat. No.4,202,879, issued to Shelton on May 13, 1980; U.S. Pat. No. 5,069,897,issued to Orr on Dec. 3, 1991; which descriptions are incorporatedherein by reference.

The modified silicone carriers suitable for use in the antiperspirantgel-solid stick compositions include, but are not limited to, compoundsor materials as defined hereinabove and which are generallycharacterized as follows: silicone polyethers or silicone glycols (suchas dimethicone copolyol); silicone alkyl-linked polyethers (such asGoldschmidt EM-90 or EM-97); siloxane surfactants of a pendant/rake/combconfiguration, silicone surfactants of a trisiloxane configuration, andsilicone surfactants of an ABA/alpha-omega block copolymers (such aspolyoxyalkylenes, polyoxyethylene or ethoxylated,polyoxyethylene/polyoxypropylene or ethoxylated/propoxylated); aromaticsubstituted silicone emollients (such as phenyl, alpha-methyl styryl,styryl, methylphenyl, alkylphenyl); silicone copolymers with otherfunctional groups include: hydrogen, alkyl, methyl, amino,trifluoropropyl, vinyl, alkoxy, arylalkyl, aryl, phenyl, styryl,polyethers, esters, carboxylics; alkylmethyl siloxanes or silicone waxes(such as hexyl, octyl, lauryl, cetyl, stearyl); nonionic functionalsiloxane copolymers with terminal groups being silanol ortrimethylsiloxy; nonionic functional siloxanes with backbone groupsbeing trisiloxane or methicone linked; nonionic silicone surfactants;tetraethoxysilane; tetramethoxysilane; hexamethoxysilicone;oxmethoxytrisiloxane; silicone emulsifiers; silicone or siloxane resins,alkyl silicone resins, polyoxyalkylene silicone resins; MQ Resins suchas Shiseido/Shin-etsu, e.g. Japanese Patent Publication JP86143760 orfrom Walker Chem. 6MBH (described in EP722970); alkoxysiloxanes;alkoxysilanes; methicones (polymethylalkylsiloxanes); and combinationsthereof.

Nonlimiting examples of suitable modified silicone carriers for use inthe antiperspirant gel-solid stick compositions herein include thefollowing modified silicones available from Dow Corning: DC-556 CosmeticGrade Fluid (phenyl trimethicone); DC-704 Diffusion Pump Fluid(Tetramethyl-Tetraphenyl-Trisiloxane); DC-705 Diffusion Pump Fluid;DC-1784 Emulsion; DC-AF Emulsion; DC-1520-US Emulsion; DC-593 Fluid(Dimethicone and! Trimethylsiloxysilicate); DC-3225C Fluid(Cyclomethicone and! Dimethicone Copolyol); DC-190 Fluid (DimethiconeCopolyol); DC-193 Fluid (Dimethicone Copolyol); DC-1401 (Cyclomethiconeand! Dimethiconol); DC-5200 Fluid (Laurylmethicone Copolyol); DC-6603Polymer Powder; DC-5640 Powder; DC-Q2-5220 (Dimethicone Copolyol); DCQ2-5324 (Dimethicone Copolyol); DC-2501 Cosmetic Wax (DimethiconeCopolyol); DC-2502 Fluid (Cetyl Dimethicone); DC-2503 Wax (StearylDimethicone); DC-1731 Volatile Fluid (Caproyl Trimethicone); DC-580 Wax(Stearoxytrimethylsilane and! Stearyl Alcohol); DC-1-3563(Dimethiconal); DC-X2-1286 (Dimethiconol); DC-X2-1146A (Cylcomethiconeand! Dimethiconol); DC-8820 Fluid (Amino functionalized); DC Q5-0158Awax (stearoxytrimethylsilane); DC-Q2-8220(Trimethylsilylamodimethicone); DC-7224 (Trimethylsilylamodimethicone);DC-X2-1318 Fluid (Cyclomethicone and! Vinyldimethicone); DC-QF1-3593Afluid (Trimethylsiloxysilicate) and combinations thereof.

Other nonlimiting examples of suitable modified silicone carriers foruse in the antiperspirant gel-solid stick compositions herein includethe following modified silicones available from General Electric: GESF-1023 (Dimethyl-Diphenyl-Siloxane); GE CF-1142 (Methylphenyl SiloxaneFluid); GE SF-1153 (Dimethyl-Diphenyl-Siloxane); GE SF-1265(Diphenyl-DimethylSiloxane); GE SF-1328; GE SF-1188 (Dimethiconecopolyol); GE SF-1188A (Silicone polyether copolymer); GE SF-1288(silicone polyether copolymer, dimethyl-methyl 3-hydroxypropylethoxylated); GE SF-1318 (Methylester Siloxane); GE SF-1328 (siliconesurfactant, dimethyl-methyl 3-hydroxypropyl ethoxylated-propoxylated);GE SF-1550 (methylphenyl siloxane, hexamethyl-3-phenyl-3-trimethylsilyl!oxy!trisiloxane); GE SF-1632 (silicone wax); GE SS-4267(Dimethicone and! Trimethylsiloxysilicate) and combinations thereof.

Other nonlimiting examples of suitable modified silicone carriers foruse in the antiperspirant gel-solid stick compositions herein includethe following modified silicones available from Goldschmidt: Abil EM-90(silicone emulsifier); Abil EM-97 (polyether siloxane); Abil Wax 9810(silicone wax or C24-28 methicone); Abil Wax 2434 (StearoxyDimethicone); Abil Wax 9800D (Stearyl Dimethicone); Tegomer H-Si 2111,H-Si 2311, A-Si 2120, A-Si 2320, C-Si 2141, C-Si 2341, E-Si 2130, E-Si2330, V-Si 2150, V-Si 2550, H-Si 6420, H-Si 6440, H-Si 6460 (Alpha-OmegaDimethicone Copolymers) and combinations thereof.

Other nonlimiting examples of suitable modified silicone carriers foruse in the antiperspirant gel-solid stick compositions herein includethe following: Masil 756 from PPG Industries (TetrabutoxypropylTrisiloxane); bis-phenylhexamethicone (available as Silbione Oils 70633V30 from Rhone-Poulenc); Silbione Oils 70646 (dimethicone. copolyolsfrom Rhone-Poulenc); Silicone L-71 1, L-720, L-721 and L722 (dimethiconecopolyols from Union Carbide); Silicone L-7000, L-7001, L-7002, L-7004,L-7500, L-7600, L-7602, L-7604, L-7605, and L-7610 (dimethiconecopolyols from Union Carbide); Unisil SF-R (dimethiconol from UPI);Silicate Cluster from Olin (Tris tributoxysiloxy!methylsilane); siliconecopolymer F-754 (dimethicone copoly from SWS Silicones); andcombinations thereof.

The anhydrous liquid carrier preferably comprises a volatile siliconecarrier. These volatile silicone carriers may be cyclic, linear orbranched chain silicones having the requisite volatility defined herein.Non-limiting examples of suitable volatile silicones are described inTodd et al., "Volatile Silicone Fluids for Cosmetics", Cosmetics andToiletries, 91:27-32 (1976), which descriptions are incorporated hereinby reference. Preferred among these volatile silicones are the cyclicsilicones having from about 3 to about 7, more preferably from about 4to about 5, silicon atoms. Most preferably are those which conform tothe formula: ##STR2## wherein n is from about 3 to about 7, preferablyfrom about 4 to about 5, most preferably 5. These volatile cyclicsilicones generally have a viscosity value of less than about 10centistokes. All viscosity values described herein are measured ordetermined under ambient conditions, unless otherwise specified.Suitable volatile silicones for use herein include, but are not limitedto, Cyclomethicone D-5 (commercially available from G. E. Silicones);Dow Corning 344, and Dow Corning 345 (commercially available from DowCorning Corp.); GE 7207, GE 7158 and Silicone Fluids SF-1202 and SF-1173(available from General Electric Co.); SWS-03314, SWS-03400, F-222,F-223, F-250, F-251 (available from SWS Silicones Corp.); VolatileSilicones 7158, 7207, 7349 (available from Union Carbide); Masil SF-V (available from Mazer) and combinations thereof.

The anhydrous liquid carrier may also comprise a non-volatile siliconecarrier other than or in addition to the preferred modified siliconecarriers described hereinbefore. These non-volatile silicone carriersare preferably linear silicones which include, but are not limited to,those which conform to either of the formulas: ##STR3## wherein n isgreater than or equal to 1. These linear silicone materials willgenerally have viscosity values of up to about 100,000 centistoke,preferably less than about 500 centistoke, more preferably from about 1centistoke to about 200 centistoke, even more preferably from about 1centistoke to about 50 centistoke, as measured under ambient conditions.Examples of non-volatile, linear silicones suitable for use in theantiperspirant compositions include, but are not limited to, Dow Corning200, hexamethyldisiloxane, Rhodorsil Oils 70047 available fromRhone-Poulenc, Masil SF Fluid available from Mazer, Dow Corning 225, DowCorning 1732, Dow Corning 5732, Dow Corning 5750 (available from DowCorning Corp.); SF-96, SF-1066 and SF18(350) Silicone Fluids (availablefrom G.E. Silicones); Velvasil and Viscasil (available from GeneralElectric Co.); and Silicone L-45, Silicone L530, Silicone L-531(available from Union Carbide), and Siloxane F-221 and Silicone FluidSWS-101 (available from SWS Silicones).

The anhydrous liquid carrier may further comprise, but is preferablysubstantially free of, organic, water-immiscible, polar liquid carriersor solvents. It has been found that the antiperspirant and deodorantefficacy of the gel-solid stick compositions are improved by minimizingor eliminating the amount of polar, organic, water-immiscible, liquidcarriers or solvents in the composition. In this context, the term"substantially free" means that the gel-solid stick compositionspreferably contain less than 7%, more preferably less than about 3%,even more preferably zero percent, by weight of an organic,water-immiscible, polar liquid carrier or solvent. These polar solventsare liquid under ambient conditions and include mono and polyhydricalcohols, fatty acids, esters of mono and dibasic carboxylic acids withmono and polyhydric alcohols, polyoxyethylenes, polyoxypropylenes,polyalkoxylates ethers of alcohols, and combinations thereof, providedthat such solvents are also water-immiscible liquids under ambientconditions. Examples of some anhydrous liquid, water-immiscible, polarorganic liquid carriers or solvents are described in Cosmetics, Science,and Technology, Vol. 1, 27-104, edited by Balsam and Sagarin (1972);U.S. Pat. No. 4,202,879 issued to Shelton on May 13, 1980; and U.S. Pat.No. 4,816,261 issued to Luebbe et al. on Mar. 28, 1989, whichdescriptions are incorporated herein by reference.

The anhydrous liquid carrier may comprise anhydrous, water-miscible,polar organic liquid carriers or solvents, examples of which includeshort chain alcohols such as ethanol. These and other polar organiccarriers or solvents can be used as co-solvents for the solidnon-polymeric gellant component of the antiperspirant gel-solid stickcompositions herein. Non-limiting examples of polar co-solvents suitablefor use herein are described in U.S. Pat. No. 5,429,816. Other suitablepolar co-solvents include those described hereinabove, which arepreferably water-immiscible organic solvents, and other co-solvents suchas phthalate co-solvents, benzoate co-solvents, cinnamate esters,secondary alcohols, benzyl acetate, phenyl alkane and combinationsthereof.

The anhydrous liquid carrier may comprise other non-polar carriers suchas mineral oil, petrolatum, isohexadecane, isododecane, varioushydrocarbon oils such as the Isopar or Norpar series available fromExxon Corp. or Permethyl series available from Persperse, and any otherpolar or non-polar, water-miscible, organic carrier liquid or solventknown or otherwise safe and effective for topical application to humanskin.

The anhydrous liquid carrier may also comprise fluorochemicals such asfluorosurfactants, fluorotelemers, and perfluoropolyethers, someexamples of which are described in Cosmetics & Toiletries, UsingFluorinated Compounds in Topical Preparations, Vol. 111, pages 47-62,(Oct. 1996) which description is incorporated herein by reference. Morespecific examples of such liquid carriers include, but are not limitedto, perfluoropolymethyl isopropyl ethers, perfluoropolypropylethers,acrylamide fluorinated telomer, fluorinated amide surfactants,perfluorinated thiol surfactants. Other more specific examples include,but are not limited to, the polyperfluoroisopropyl ethers available fromDupont Performance Chemicals under the trade name Fluortress® PFPE oils,and the series fluorosurfactants from Dupont Performance Chemicals underthe trade name Zonyl® Fluorosurfactants.

Optional Nucleating Agent

The antiperspirant gel-solid stick compositions of the present inventionpreferably further comprises a nucleating agent. The nucleating agent isused to minimize gellant particle size, and/or for obtaining thepreferred gellant particle morphology described herein.

The nucleating agent for use in the antiperspirant composition of thepresent invention must be a solid material under ambient conditions andhave 1) a melting point near the melting point of the selected gellant,2) a solubility in the anhydrous liquid carrier that is less than thesolubility of the solid non-polymeric gellant in the anhydrous liquidcarrier, or 3) be in the form of an inorganic, insoluble, micronizedparticulate. Examples of suitable nucleating agents are describedhereinafter.

The concentration of the nucleating agent in the composition istypically from about 0.0001% to about 5%, preferably from about 0.001%to about 2%, more preferably from about 0.01% to about 1%, wherein themolar ratio of the solid non-polymeric gellant to the nucleating agentis from about 10:1 to about 1000:1, preferably from about 10:1 to about100:1. Preferred nucleating agents are those having a melt point of fromabout 40° C. below to about 200° C. above, more preferably from about20° C. below to about 100° C. above, the melting point of the selectedsolid non-polymeric gellant.

The antiperspirant compositions containing the nucleating agent arepreferably prepared by 1) combining the solid non-polymeric gellant,anhydrous liquid carrier and a nucleating agent as described herein, 2)heating components or the combination of components to form a solutionor other homogeneous liquid or liquid dispersion, and 3) solidifying thecombination of components by cooling the combination to below thesolidification point of the solid non-polymeric gellant to form theantiperspirant composition of the present invention. During thisprocess, the solid non-polymeric gellant is preferably melted orotherwise liquefied, and then allowed to solidify in the presence of theanhydrous liquid carrier and the nucleating agent. Also during thisprocess, the nucleating agent is typically melted or otherwise liquefied(except for micronized, inorganic nucleating agents), and then in thepresence of the anhydrous liquid carrier and the melted or liquefiedgellant, the liquified nucleating agent crystallizes, gels or otherwisesolidifies and acts as a seed or nucleus to promote formation of smallgellant nuclei during the crystallization of the gellant in theanhydrous liquid carrier.

The nucleating agent for use in the antiperspirant compositions includefatty alcohols, esters of fatty alcohols, ethoxylated fatty alcohols,esters or ethers of fatty acids including waxes, and triglycerides,silica, titanium dioxide, solid polyol carboxylic acid polyesters, andmixtures thereof.

Suitable fatty alcohols for use as nucleating agents include monohydricalcohols, ethoxylated fatty alcohols, and fatty alcohol esters. Specificexamples of commercially available fatty alcohol nucleating agentsinclude, but are not limited to, Unilin 550, Unilin 700, Unilin 425,Unilin 400, Unilin 350, and Unilin 325, all supplied by Petrolite.Suitable ethoxylated fatty alcohols include, but are not limited,Unithox 325, Unithox 400, and Unithox 450, Unithox 480, Unithox 520,Unithox 550, Unithox 720, Unithox 750, all of which are available fromPetrolite. Non-limiting examples of suitable esters of fatty alcoholsinclude tri-isostearyl citrate, ethyleneglycol di-12-hydroxystearate,tristearylcitrate, stearyl octanoate, stearyl heptanoate,trilaurylcitrate.

Suitable fatty acid esters for use as nucleating agents include esterwaxes, monoglycerides, diglycerides, triglycerides and mixtures thereof.Preferred are the glyceride esters. Non-limiting examples of suitableester waxes include stearyl stearate, stearyl behenate, palmitylstearate, stearyl octyldodecanol, cetyl esters, cetearyl behenate,behenyl behenate, ethylene glycol distearate, ethylene glycoldipalmitate, and beeswax. Examples of commercial ester waxes includeKester waxes from Koster Keunen, Crodamol SS from Croda and DemalcareSPS from Rhone Poulenc.

Preferred triglyceride nucleating agents include, but are not limitedto, tristearin, tribehenate, behenyl palmityl behenyl triglyceride,palmityl stearyl palmityl triglyceride, hydrogenated vegetable oil,hydrogenated rape seed oil, castor wax, fish oils, tripalmiten,Syncrowax HRC and Syncrowax HGL-C (Syncrowax is available from Croda,Inc.). Other suitable glycerides include, but are not limited to,glyceryl stearate and glyceryl distearate.

Preferably, the nucleating agent is a solid polyol carboxylic acidpolyester. Suitable solid polyol carboxylic acid polyesters includethose which are polyol esters or polyesters wherein the carboxylic acidester groups of the polyester comprise a combination of: (a) long chainunsaturated carboxylic acid moieties or a mixture of long chainunsaturated carboxylic acid moieties and short chain saturatedcarboxylic acid moieties, and (b) long chain saturated carboxylic acidmoieties, the ratio of (a) to (b) being from about 1 to 15 to about 2to 1. At least about 15%, preferably at least about 30%, more preferablyat least about 50%, and most preferably at least about 60% by weight ofthe total carboxylic acid moieties of the polyesters are C20 or highersaturated carboxylic acid moieties. The long chain unsaturatedcarboxylic acid moieties are typically straight chain and contain atleast about 12, preferably about 12 to about 26, more preferably about18 to about 22 carbon atoms. The most preferred unsaturated carboxylicacids are the C18 mono and/or di unsaturated carboxylic acids. The shortchain saturated carboxylic acids are typically unbranched and containabout 2 to about 12, preferably about 6 to about 12, and most preferablyabout 8 to about 12 carbon atoms. The long chain saturated carboxylicacids are typically straight chain and contain at least about 20,preferably about 20 to about 26, and most preferably about 22 carbonatoms. The molar ratio of Group (a) carboxylic acid moieties to Group(b) carboxylic acid moieties in the polyester molecule is from about1:15 to about 2:1, preferably about 1:7 to about 5:3, and morepreferably about 1:7 to about 3:5. The average degree of esterificationof these carboxylic acid esters is such that at least about 2 of thehydroxyl groups of the polyol are esterified. In the case of sucrosepolyesters from about 7 to about 8 of the hydroxyl groups of the polyolare preferably esterified. Typically, substantially all, e.g., at leastabout 85%, preferably at least about 95%, of the hydroxyl groups of thepolyol are esterified.

Preferred polyols of the solid polyol carboxylic acid esters are sugars,including monosaccharides and disaccharides and trisaccharides,containing from about 4 to about 11 hydroxyl groups. Most preferredsugars- are those which contain about 4 to about 8, more preferablyabout 6 to about 8 hydroxyl groups. Examples of those containing fourhydroxyl groups are the monosaccharides xylose, arabinose, andcombinations thereof. Suitable five hydroxyl group-containing polyolsare the monosaccharides galactose, fructose, mannose, glucose, andcombinations thereof. Examples of disaccharide polyols which can be usedinclude maltose, lactose, sucrose, and combinations thereof, all ofwhich contain eight hydroxyl groups. The preferred polyol is sucrose.

Examples of long chain unsaturated carboxylic acid moieties include, butare not limited to, lauroleate, myristoleate, palmitoleate, oleate,elaidate, erucate, linoleate, linolenate, arachidonate,eicosapentaentoate, and docosahexaenoate. For oxidative stability, themono- and diunsaturated fatty acid moieties are preferred.

Examples of suitable short chain saturated carboxylic acid moietiesinclude, but are not limited to, acetate, caproate, caprylate, caprate,and laurate.

Examples of suitable long chain saturated carboxylic acid moietiesinclude, but are not limited to, arachidate, behenate, lignocerate, andcerotate.

Of course, the long chain unsaturated carboxylic acid moieties can beused singly or in mixtures with each other or in mixtures with the shortchain saturated carboxylic acid moieties, in all proportions. Likewise,the long chain saturated carboxylic acid moieties can be used incombination with each other in all proportions. Mixed carboxylic acidmoieties from source oils which contain substantial amounts of thedesired unsaturated or saturated acids can be used as the acid moietiesto prepare compounds for use as nucleating agents herein. The mixedcarboxylic acids from the oils should contain at least about 30%,preferably at least about 50%, and most preferably at least about 80% ofthe desired unsaturated or saturated acids. For example, rapeseed oilfatty acids or soybean oil fatty acids can be used instead of pureC12-C16 unsaturated fatty acids. Hardened, i.e. hydrogenated, higherucic rapeseed oil fatty acids can be used instead of pure. C20-C26saturated acids, Preferably the C20 and higher acids, or theirderivatives, e.g. methyl or other low alkyl esters, are concentrated forexample by distillation. The fatty acids from palm kernal oil or coconutoil can be used as a source of C8 to C12 acids, An example of the use ofsource oils to make solid polyol polyesters for use in theantiperspirant compositions herein is the preparation of solid sucrosepolyester, employing the fatty acids of high oleic sunflower oil andsubstantially completely hydrogenated high erucic rapeseed oil. Whensucrose is substantially completely esterified with a 1:3 by weightblend of the methyl esters of the fatty acids of these two oils, theresulting sucrose polyester will have a molar ratio of unsaturated C18acid radicals to C20 and higher saturated acid radicals of about 1:1 andabout 28.6 weight percent of the total fatty acids in the polyester willbe C22 fatty acids.

The higher the proportions of the desired unsaturated and saturatedacids in the carboxylic acid stocks used in making the solid polyolpolyester, the more efficient the ester will be in its ability tofunction as a nucleating agent.

Examples of solid polyol carboxylic acid polyester nucleating agents foruse in the antiperspirant composition herein include, but are notlimited to, the octaester of raffinose in which the esterifyingcarboxylic acid moieties are linoleate and behenate in a 1:3 molarratio; the heptaester of maltose wherein the esterifying carboxylic acidmoieties are sunflower seed oil fatty acids and lignocerate in a 3:4molar ratio; the octaester of sucrose wherein the esterifying carboxylicacid moieties are oleate and behenate in a 2:6 molar ratio; and theoctaester of sucrose wherein the esterfying carboxylic acid moieties arelaurate, linoleate and behenate in a 1:3:4 molar ratio. A preferredmaterial is sucrose polyester in which the degree of esterification is7-8, and in which the fatty acid moieties are C18 mono- and/ordi-unsaturated and behenic, in a molar ratio of unsaturates:behenic of1:7 to 3:5. A particularly preferred polyol ester nucleating agent isthe octaester of sucrose in which there are about 7 behenic fatty acidmoieties and about 1 oleic moiety in the molecule.

The solid carboxylic acid polyesters herein can be made according toprior art known methods for preparing polyesters of polyols. See, forexample U.S. Pat. No. 5,306,516, to Letton et al., issued Apr. 26, 1994;U.S. Pat. No. 5,306,515, to Letton et al., issued Apr. 26, 1994; U.S.Pat. No. 5,305,514, to Letton et al., issued Apr. 26, 1994; U.S. Pat.No. 4,797,300, to Jandacek et al., issued Jan. 10, 1989; U.S. Pat. No.3,963,699, to Rizzi et al., issued Jun. 15, 1976; U.S. Pat. No.4,518,772, to Volpenhein, issued May 21, 1985; and U.S. Pat. No.4,517,360, to Volpenhein, issued May 21, 1985; all of which areincorporated by reference herein in their entirety.

Suitable inorganic, micronized, non-solubilized nucleating agents foruse in the antiperspirant compositions include materials such as silica,titanium dioxide and combinations thereof. These materials containsubmicron particles (average particle size generally less than about 1μm) which aid in the production of small gellant crystals or particles.

Preferred nucleating agents, and preferred concentrations of thenucleating agents, for use in the antiperspirant compositions includeC18 succinic acid (0.1%), 1,9-nonanedioc acid (0.1%), Teflon (0.1%),silica (0.1%), polysiloxane copolymer (2%), sucrose octabehenate (0.5%,0.75%, 1.0%), Unilin 350 (0.1%), Unilin 550 (0.1%), Unilin 700 (0.1%) ,trihydroxystearin (0.1%) and combinations thereof.

Optional Components

The antiperspirant gel-solid stick compositions of the present inventionmay further comprise one or more optional components which may modifythe physical, chemical or aesthetic characteristics of the compositionsor serve as additional "active" components when deposited on the skin.The compositions may also further comprise optional inert ingredients.Many such optional materials are known in the antiperspirant art and maybe used in the antiperspirant compositions herein, provided that suchoptional materials are compatible with the essential materials describedherein, or do not otherwise unduly impair product performance.

Non-limiting examples of optional materials include active componentssuch as bacteriostats and fungiostats, and "non-active" components suchas colorants, perfumes, emulsifiers, chelants, distributing agents,preservatives, residue masking agents, process aides such as viscositymodifiers, and wash-off aids. Examples of such optional materials aredescribed in U.S. Pat. No. 4,049,792, Elsnau, issued Sep. 20, 1977;Canadian Patent 1,164,347, Beckmeyer et al., issued Mar. 27, 1984; U.S.Pat. No. 5,019,375, Tanner et al., issued May 28, 1991; and U.S. Pat.No. 5,429,816, Hofrichter et al., issued Jul. 4, 1995; whichdescriptions are incorporated herein by reference.

The antiperspirant gel-solid stick compositions of the present inventioncan also be formulated to comprise other dispersed solids or othermaterials in addition to or in place of the particulate antiperspirantactive. Such other dispersed solids or other materials include anymaterial known or otherwise suitable for topical application to humanskin. The antiperspirant gel-solid stick compositions can also beformulated as gel-solid stick compositions which contain noantiperspirant or other active material, particulate or otherwise.

Method of Manufacture

The antiperspirant gel-solid stick compositions of the present inventionmay be prepared by any known or otherwise effective technique, suitablefor providing an antiperspirant gel-solid stick composition having therequisite crystalline matrix and other product characteristics describedherein. Such methods involve formulation of the essential components ofthe composition to form a gel-solid having the requisite elastic toviscous moduli ratio, product hardness, and visible residue index,wherein the crystalline matrix within the composition compriseselongated non-polymeric gellant crystals having an aspect ratio ofgreater than about 2, preferably greater than about 6, and an averageparticle diameter that is minimized (preferably to less than about 1 μm)through techniques directed to minimizing crystalline particle size in acomposition.

Crystalline particle size in the preferred embodiments of the presentinvention can be determined by techniques well known in the art, whichincludes light or electron microscopy of the composition, wherein thecomposition is formulated for analysis purposes without particulateantiperspirant active or other solid particulates. Without suchreformulation, it is more difficult to directly determine anddistinguish crystalline gellant particle size and morphology from theparticle size and morphology contributed from other non-gellantparticulates. The reformulated composition is then evaluated by light orelectron microscopy or other similar method.

Techniques for preparing the antiperspirant gel-solid stick compositionsof the present invention include those methods suitable for formulatingcompositions containing small gellant crystalline particles. Suitabletechniques for minimizing crystalline gellant particle size include theuse of nucleating agents, formulation with select carriers or gellantsor carrier/gellant combinations, controlling rates of crystallizationincluding controlling formulation, controlling process flow rate, andprocessing temperatures, and other methods described herein. All suchmethods should be applied to the formulation to control or minimizegellant crystal particle size, and/or to form the desired elongatedcrystalline particles, to thus form the desired crystalline matrix ofthe composition.

Method of Use

The antiperspirant gel-solid stick compositions may be applied topicallyto the axilla or other area of the skin in an amount effective to treator reduce perspiration wetness and malodor. The composition ispreferably applied in an amount ranging from about 0.1 gram to about 20grams, more preferably from about 0.1 gram to about 10 grams, even morepreferably from about 0.1 gram to about 1 gram, to the desired area ofthe skin. The compositions are preferably applied to the axilla or otherarea of the skin, one or two times daily, preferably once daily, toachieve effective antiperspirant and malodor control over an extendedperiod.

EXAMPLES

The following non-limiting examples illustrate specific embodiments ofthe antiperspirant gel-solid stick compositions of the presentinvention, including methods of manufacture and use.

Each of the exemplified compositions are prepared by combining all ofthe listed components except the antiperspirant active and othermaterials such as perfumes. The combined components are heated to about100° C. with agitation to form a hot liquid, after which all othermaterials are added to the heated liquid. The heated liquid is allowedto cool with agitation until just before the point of solidification, atwhich point the cooled, liquid composition is filled into applicatorpackages and allowed to cool and solidify to the requisite producthardness.

Each of the exemplified compositions comprise a crystalline gel matrixcontaining crystalline particles having an aspect ratio of greater thanabout 6, and an average crystalline gellant particle size of less thanabout 1 μm. Each of the exemplified compositions also have a visibleresidue index of between about 11 and about 30 L-value, a producthardness of between about 500 and 5,000 gram.force, and a G'/G" ratio ofbetween about 0.1 and about 100. Each of the exemplified antiperspirantcompositions are applied topically to the axilla area of the skin, inaccordance with the methods of use described herein, and provideimproved low residue performance, efficacy and aesthetics.

    __________________________________________________________________________    Examples 1-8                                                                  Component  No. 1                                                                             No. 2                                                                             No. 3                                                                             No. 4                                                                             No. 5                                                                             No. 6                                                                             No. 7                                                                             No. 8                                  __________________________________________________________________________    D5 Cyclomethicone.sup.1                                                                  47.8                                                                              47.8                                                                              48  48  48  40.5                                                                              47.8                                                                              45.5                                   Petrolatum --  --  --  --  --  --  --  15.75                                  Octyldodecanol                                                                           14.0                                                                              14.0                                                                              14.0                                                                              14.0                                                                              14.0                                                                              --  14.0                                                                              4.0                                    12-Hydroxystearic Acid                                                                   9.0 7.0 --  --  7.5 8.0 7.0 6.75                                   C20-40 alcohols.sup.2                                                                    0.5 0.5 0.5 0.5 0.5 --  0.5 --                                     Dimethicone Copolyol.sup.3                                                               --  2.0 --  --  --  --  --  --                                     C20-40 Pareth-10.sup.4                                                                   1.25                                                                              1.25                                                                              1.25                                                                              1.25                                                                              1.25                                                                              --  1.25                                                                              2.0                                    C20-40 Pareth-40.sup.5                                                                   1.25                                                                              1.25                                                                              1.25                                                                              1.25                                                                              1.25                                                                              --  1.25                                                                              --                                     N-isopropyl-12-hydroxy                                                                   --  --  9.0 --  --  --  --  --                                     stearamide                                                                    Sodium EDTA                                                                              0.2 0.2 --  --  --  --  0.2 --                                     C12-15 Alkylbenzoate.sup.6                                                               --  --  --  --  --  25                                             Triacetin  --  --  --  --  1.5 --  --  --                                     Soybean oil                                                                              --  --  --  --  --  --  2.0 --                                     12-hydroxystearamide                                                                     --  --  --  9.0 --  --  --  --                                     Al Zr tri chlorohydrex                                                                   26  26.0                                                                              26  26  26  26  26  26                                     glycinate                                                                     Residue (l-value)                                                                        29.5                                                                              27  24  30  29  30  29  30                                     Hardness (gram · force)                                                         1480                                                                              1150                                                                              2500                                                                              800 650 900 1090                                                                              1000                                   G'/G" ratio                                                                              10  10  20  5   5   10  10  10                                     __________________________________________________________________________     .sup.1 Dow Corning 245 Fluid; General Electric SF1202                         .sup.2 Petrolite Unilin 425                                                   .sup.3 Dow Corning 3225C                                                      .sup.4 Petrolite Unithox 450                                                  .sup.5 Petrolite Unithox 480                                                  .sup.6 Finsolv TN from Finetex                                           

What is claimed is:
 1. An anhydrous antiperspirant gel-solid stickcompositions comprising:(A) from about 0.5% to about 60% by weight ofparticulate antiperspirant active; (B) from about 1% to about 15% byweight of a solid non-polymeric gellant selected from the groupconsisting of 12-hydroxystearic acid, esters of 12-hydroxystearic acid,amides of 12-hydroxystearic acid, and combinations thereof; and (C) fromabout 10% to about 80% by weight of an anhydrous liquid carrier havingan average solubility parameter of from about 3 to about 13 (cal/cm³)⁰.5andwherein the composition has a visible residue index of from about 11to about 30 L-value, a product hardness of from about 500 gram.force toabout 5,000 gram.force, and a ratio of an elastic to viscous moduli offrom about 0.1 to about 100, and wherein the refractive indices of theparticulate antiperspirant active, the solid non-polymeric gellant, andthe anhydrous liquid carrier are not matched, and wherein the solidnon-polymeric gellant in the composition is in the form of elongatedcrystalline particles having an aspect ratio of at least about 2 and anaverage gellant particle size of less than about 1 μm.
 2. Thecomposition of claim 1 wherein the solid non-polymeric gellant isselected from the group consisting of 12-hydroxystearic acid,12-hydroxystearic acid methyl ester, 12-hydroxystearic acid ethyl ester,12-hydroxystearic acid stearyl ester, 12-hydroxystearic acid benzylester, 12-hydroxystearic acid amide, isopropyl amide of12-hydroxystearic acid, butyl amide of 12-hydroxystearic acid, benzylamide of 12-hydroxystearic acid, phenyl amide of 12-hydroxystearic acid,t-butyl amide of 12-hydroxystearic acid, cyclohexyl amide of12-hydroxystearic acid, 1-adamantyl amide of 12-hydroxystearic acid,2-adamantyl amide of 12-hydroxystearic acid, diisopropyl amide of12-hydroxystearic acid, and combinations thereof.
 3. The composition ofclaim 2 wherein the solid non-polymeric gellant is 12-hydroxystearicacid.
 4. The composition of claim 1 wherein the solid non-polymericgellant are elongated crystalline particles having an aspect ratio of atleast about
 6. 5. The composition of claim 1 wherein the composition hasa Differential Scanning Calorimeter onset temperature of from about 25°C. to about 85° C.
 6. The composition of claim 5 wherein the compositionhas a Differential Scanning Calorimeter onset temperature of from about30° C. to about 60° C.
 7. The composition of claim 4 wherein the solidnon-polymeric gellant are crystalline particles having an averageparticle size of less than about 0.2 μm.
 8. The composition of claim 1wherein the composition has a product hardness of from about 750gram.force to about 2,000 gram.force.
 9. The composition of claim 7wherein the composition has a ratio of an elastic to viscous moduli offrom about 0.1 to about
 50. 10. The composition of claim 9 wherein therefractive indices of the particulate antiperspirant active, the solidnon-polymeric gellant, and the anhydrous liquid carrier differ by morethan 0.04.
 11. The composition of claim 2 wherein the anhydrous liquidcarrier comprises a volatile silicone carrier.
 12. The composition ofclaim 11 wherein the anhydrous liquid carrier further comprises anon-volatile silicone carrier having a viscosity of less than about100,000 centistokes.
 13. A method for treating or reducing perspirationwetness and malodor, comprising applying from about 0.1 gram to about 20grams of the composition of claim 1 to the desired area of the skin. 14.A method for treating or reducing perspiration wetness and malodor,comprising applying from about 0.1 gram to about 20 grams of thecomposition of claim 11 to the desired area of the skin.